Flexible filament vegetation cutting devices are known in which a coil of flexible cutting element is wound on a spool which is rotated about a substantially vertical axis to cause a free end of the cutting element to define a cutting plane. Such devices have been further developed into bump-feed trimmers.
A bump-feed trimmer is disclosed in United Kingdom Pat. No. 1,574,382 of The Toro Company. This discloses an escapement mechanism comprising two discs having inwardly projecting teeth and being sandwiched together and secured to a filament spool with the aid of a plurality of screws to define a spool assembly. The spool assembly is resiliently urged downwardly in a housing by a coil spring. Movement of the spool assembly axially relative to a drive member causes the spool assembly to be temporarily disconnected therefrom with the result that a discrete increment of filament unwinds from the spool. This operation is performed in use by "bumping" the trimmer head on the ground.
However, with the above disclosed bump-feed trimmer, the mechanism of the trimmer head is somewhat complicated to assemble. Also, the complete trimmer head has to be removed in order to replenish the supply of cutting filament or string.